package org.bouncycastle.asn1.pkcs;

import java.util.Enumeration;

import org.bouncycastle.asn1.ASN1EncodableVector;
import org.bouncycastle.asn1.ASN1Sequence;
import org.bouncycastle.asn1.ASN1Set;
import org.bouncycastle.asn1.BERSequence;
import org.bouncycastle.asn1.DEREncodable;
import org.bouncycastle.asn1.DERInteger;
import org.bouncycastle.asn1.DERObject;
import org.bouncycastle.asn1.DERTaggedObject;

/**
 * a PKCS#7 signed data object.
 */
public class SignedData implements DEREncodable, PKCSObjectIdentifiers {
    private DERInteger version;
    private ASN1Set digestAlgorithms;
    private ContentInfo contentInfo;
    private ASN1Set certificates;
    private ASN1Set crls;
    private ASN1Set signerInfos;

    public static SignedData getInstance(Object o) {
        if (o instanceof SignedData) {
            return (SignedData) o;
        } else if (o instanceof ASN1Sequence) {
            return new SignedData((ASN1Sequence) o);
        }

        throw new IllegalArgumentException("unknown object in factory: " + o);
    }

    public SignedData(DERInteger _version, ASN1Set _digestAlgorithms, ContentInfo _contentInfo, ASN1Set _certificates, ASN1Set _crls,
            ASN1Set _signerInfos) {
        version = _version;
        digestAlgorithms = _digestAlgorithms;
        contentInfo = _contentInfo;
        certificates = _certificates;
        crls = _crls;
        signerInfos = _signerInfos;
    }

    public SignedData(ASN1Sequence seq) {
        Enumeration e = seq.getObjects();

        version = (DERInteger) e.nextElement();
        digestAlgorithms = ((ASN1Set) e.nextElement());
        contentInfo = ContentInfo.getInstance(e.nextElement());

        while (e.hasMoreElements()) {
            DERObject o = (DERObject) e.nextElement();

            //
            // an interesting feature of SignedData is that there appear to be varying implementations...
            // for the moment we ignore anything which doesn't fit.
            //
            if (o instanceof DERTaggedObject) {
                DERTaggedObject tagged = (DERTaggedObject) o;

                switch (tagged.getTagNo()) {
                    case 0:
                        certificates = ASN1Set.getInstance(tagged, false);
                        break;
                    case 1:
                        crls = ASN1Set.getInstance(tagged, false);
                        break;
                    default:
                        throw new IllegalArgumentException("unknown tag value " + tagged.getTagNo());
                }
            } else {
                signerInfos = (ASN1Set) o;
            }
        }
    }

    public DERInteger getVersion() {
        return version;
    }

    public ASN1Set getDigestAlgorithms() {
        return digestAlgorithms;
    }

    public ContentInfo getContentInfo() {
        return contentInfo;
    }

    public ASN1Set getCertificates() {
        return certificates;
    }

    public ASN1Set getCRLs() {
        return crls;
    }

    public ASN1Set getSignerInfos() {
        return signerInfos;
    }

    /**
     * Produce an object suitable for an ASN1OutputStream.
     * 
     * <pre>
     *  SignedData ::= SEQUENCE {
     *      version Version,
     *      digestAlgorithms DigestAlgorithmIdentifiers,
     *      contentInfo ContentInfo,
     *      certificates
     *          [0] IMPLICIT ExtendedCertificatesAndCertificates
     *                   OPTIONAL,
     *      crls
     *          [1] IMPLICIT CertificateRevocationLists OPTIONAL,
     *      signerInfos SignerInfos }
     * </pre>
     */
    public DERObject getDERObject() {
        ASN1EncodableVector v = new ASN1EncodableVector();

        v.add(version);
        v.add(digestAlgorithms);
        v.add(contentInfo);

        if (certificates != null) {
            v.add(new DERTaggedObject(false, 0, certificates));
        }

        if (crls != null) {
            v.add(new DERTaggedObject(false, 1, crls));
        }

        v.add(signerInfos);

        return new BERSequence(v);
    }
}
